Want to claim your city as your own? Competing with a rival gang for turf, and want to avoid messy knife fights? Well now you can, thanks to Urban Defender. Working over a short time period, a team of students from Zurich University of Arts built a system to claim buildings by throwing a specially equipped ball at them. Impacts are detected by an accelerometer connected to an Arduino, which is wirelessly connected to a Beagle board which uses a GPS to coordinate the hit to a specific address.

They apparently didn’t have time to finish the multi-player version of the game, but I think the concept is too good to let die. Someone should definitely hook this up to the social networking game foursquare. As a bonus, you could use the sensor units to play the actual game four square when you get tired of fighting for turf.

They have played a quite similar game in the rougher ends of town for some time now.

The concept of claiming ‘turf’ is on the whole much the same, but implemented with much lower tech.
If I remember correctly the ‘balls’ were constructed from discarded bottles of some manner. Instead of a Beagle board and GPS they simply used a liquid of some sort, usually petrol, and and old piece of cloth.

Its a charming game, but I haven’t had the temerity to ask the indigenous dwellers of the region the precise rules or exactly how it is correctly played.